Efficacy and Effectiveness of Cochlear Implants in Deaf Children

Abstract

A large body of clinical research over the last decade demonstrates that cochlear implants work and provide significant speech and language benefits to profoundly deaf adults and prelingually deaf children. The most challenging research problem today is that cochlear implants do not work equally well for everyone who has a profound hearing loss and cochlear implants frequently do not provide much benefit at all under highly degraded listening conditions. Some individuals do extremely well on traditional audiologic outcome measures with their cochlear implants when tested under benign listening conditions in the clinic and research laboratory while others have much more difficulty. However, all patients with cochlear implants uniformly have difficulty in a number of challenging perceptual domains such as: listening in noise, talking on the telephone, localizing sounds, recognizing familiar voices and different dialects, identifying environmental sounds and listening to music. The enormous variability in outcome and benefit following implantation is not surprising because none of the current generation of cochlear implants successfully restores normal hearing or supports robust speech perception and spoken language processing across all of these difficult and highly variable listening conditions. The traditional outcome measures of audiologic benefit were never designed to assess, understand or explain individual differences in speech perception and spoken language processing. In this chapter, we summarize recent findings that suggest several promising new directions for understanding and explaining variability in outcome and benefit after implantation. These results have implications for the design of new cochlear implants as well as the development of radically new approaches to intervention, training and habilitation following implantation.